Engine generator

Abstract

It is an object of the invention to improve a cooling efficiency for cooling an engine generator by dividing a cooling air passage into two routes. The engine generator includes an engine, a generator, a muffler and a cooling fan, which are all enclosed in a housing. A first cooling air passage is formed adjacent to a cylinder of the engine. A second cooling air passage is formed beneath the engine, extending from the lower side of the cooling fan, passing through an area below the engine and arriving at the muffler. The second cooling air passage is formed between an oil pan and a vibration isolation support base plate, with the oil pan facing the second cooling air passage. In this way, an air supplied from the cooling fan is divided into two routes, with one cooling the cylinder head of the engine and the other the lower portion of the engine and the muffler. When the second cooling passage is partially formed by the vibration isolation support base plate, a longer span can be obtained by the vibration isolation support base plate. Therefore, a vibration isolation member is provided on each end of the vibration isolation support base plate for effectively reducing the engine vibration.

What is claimed is:  
     
       1. An engine generator comprising: 
       a base;  
       an engine disposed on the base;  
       a generator driven by the engine;  
       a muffler positioned on the exhaust side of the engine;  
       a cooling fan driven by the engine;  
       a housing enclosing the engine, the generator, the muffler and the cooling fan;  
       a first cooling air passage formed on the cylinder head side of the engine for cooling the upper portion of the engine by a cooling air supplied from the cooling fan; and  
       a second cooling air passage extending from the lower side of the cooling fan and passing under the lower side of the engine and arriving at the muffler for cooling the lower portion of the engine and the muffler by said cooling air supplied from the cooling fan.  
     
     
       2. An engine generator according to  claim 1 , wherein: 
       the engine has an oil pan disposed to face the second cooling air passage.  
     
     
       3. An engine generator according to  claim 1 , wherein: 
       the second cooling air passage is formed between the oil pan of the engine and a vibration isolation support base plate attached under the engine and extending parallel to a crank shaft of the engine.  
     
     
       4. An engine generator according to  claim 3 , further comprising: 
       a plurality of vibration isolation support plates provided on end portions of the vibration isolation support base plate for supporting the vibration isolation support base plate;  
       a plurality of brackets provided on the base of the engine generator wherein each bracket faces a corresponding vibration isolation support plate; and  
       a plurality of vibration isolation members interposed between vibration isolation support plates and brackets, for inhibiting a transmission of an engine vibration through the vibration isolation support plates towards the brackets.  
     
     
       5. An engine generator according to  claim 4 , wherein: 
       the vibration isolation support base plate is formed in a size being longer than a length of the engine in a crank shaft extending direction.  
     
     
       6. An engine generator according to  claim 1 , wherein: 
       the first cooling air passage is formed within a cover of the fan, extending from outside of the cooling fan through an upper side of the engine and to an upper side of the muffler.